Powder actuated tool



POWDER ACTUATED TOOL Filed May 4, 1965 N mf @VN DMN @MN NNN RN 'ITQNN um Q vw www www D mm wwmm .VN M1 mz 7 r. n mm um ,m vw www@ @Q Q wm mK @Rum @www EN w wv@ NT @uw N h l HOY 6I IVE/@HORN RAYMOND I( POMEROY WNN QNN ATTORNEYS N0v- 8, 1966 R. G. NEIGHORN ETAL 3,283,983

POWDER ACTUATED TOOL Filed May 4, 1965 2 Sheets-Sheet 2 BUC/(HORN, BLORE, /fL/IROU/ST SPAR/(MAN ATTORNEYS United States Patent O 3,283,983 PWDER ACTUATED TOOL Roy G. Neiglxorn, Raymond V. Pomeroy, and Dale L.

Robinson, Portland, Greg., assgnors to @mark Industries, Inc., Portland, Oreg., a corporation of Oregon Filed May 4, 1965, Ser. No. 453,136 Claims. (Cl. 227-11) This invention relates to a powder actuated tool, and more particularly to a powder actuated tool with a recoil absorber.

Powder actuated tools have an important role, particularly in the construction industry, to secure fasteners in walls, oors and the like, and are very extensively used. However, the powder actuated tools known hitherto and used up to several years ago, have been of the high velocity type. Within the last few years a low velocity captive piston tool providing greater safety has been developed and used quite extensively. This type of tool minimizes the possibility of accidents, but due to the mass of the captive piston, results in much higher recoil than the high velocity tools. The extremely high recoil yof this type of tool yhas limited its use to light duty fasteners. It would be desirable to provide a llow velocity captive piston tool which is capable of driving medium and heavy duty fasteners with larger diameter a-nd longer Shanks than has hitherto been possible in this type of tool. A further problem has been present in powder actuated tools of the captive pist-on type which have a captive piston provided with a large piston portion, which tapers in a transition portion to a smaller diameter ram portion adapted to enter a bore of a muzzle of the barrel of the powder actuated tool, and in which the barrel has a tapered portion complementary to the transition portion to effectuate drawing of the transition portion. When the t-ool is fired without sufcient resistance encountered by the captive piston, the

barrel portion often is damaged by such accidental tiring l of the tool and has to be replaced. The main portion of the barrel usually is undamaged and it would be desirable to be able to replace just the damaged muzzle portion of the barrel. It would also be desirable to provide a captive ypiston powder actuated tool in which a power plug assembly including a piston cage is provided with a tapped portion adapted to receive a threaded power plug, the plug being interchangeable with plugs adapted to hold `different size cartridge An object of the invention is to provide a new and improved powder actuated tool.

Another object of the invention is to provide a powder actuated tool with a recoil absorber.

A further object of the invention is to provide a powder actuated tool having a pad of resilient, compressible material adapted to resist recoil movement of a firing mechanism of the tool to dissipate the recoil forces.

Yet another object of the invention is to provide a powder actuated ltool having a recoil pad of foam-like, resilient plastic material having the characteristic of high energy absorption during compression and also having a slow recovery characteristic.

A still further object of the invention is to provide a powder actuated tool in which a recoil absorber is positioned between a free lloating firing mechanism and a handle.

A still further object of the invention is to provide a powder actuated tool having a trigger mechanism which cannot be red from shock, such as that occurring, for example, in dropping the tool.

Another object of the invention is to provide a powder actuated tool having a power plug assembly including a 3,283,983 Patented Nov. 8, 1966 captive piston and a collet-like piston cage together with a removable cartridge carrying plug `mounted in the sleeve.

Yet another object of the invention is to provide a powder actuated tool including a barrel provided wit-h a separable muzzle portion.

The invention provides a powder actuated tool preferably having a pad of resilient, compressible material compressed by recoil of a breech block subsequent to tiring the tool to absorb and dissipate the energy of recoil. The pad preferably is a partially precompressed, elongated mass of foam-like plastic material having high energy absorption and a slow recovery characteristic. The tool also is preferably provided with a novel tiring mechanism including a lightweight Ihammer and firing pin actuated by a light spring action so that accidental tiring from shock occ-urring as, for example, in dropping the tool is prevented. Another feature preferably included in the tool is that of a power plug assembly having a piston cage provided with collet-like gripping fingers and along which is slidable a captive piston having an elongated, smaller ram portion with a cartridge-holding power plug threaded into a tapped end portion of the piston cage. Preferably there also is provided a muzzle portion having a bore slidab-ly receiving a fastener and adapted to slidably receive the ram porti-on, and also having a tapered end adapted to receive a soft, d-rawable, tapered transition portion of the captive piston to draw down the transition portion when the-re is no opposition to movement of the piston. The 'muzzle portion preferably is detachably secured tio the barrel.

A complete understanding of the invention may be obtained from the following detailed description of a powder actuated tool forming a specific embodiment thereof, wlhen read in conjunction with the appended drawings, in which:

FIG. l is a vertical sectional View of a powder actuated tool forming one embodimentof the invention;

FIGS. 2 to 5 are enlarged, vertical sectional views taken respectively along lines 2 2, 3 3, 4 4 and 5 5 of FIG. 1;

FIG. 6 is an enlarged, vertical sectional view of a portion of the powder actuated tool of FIG. 1, with parts thereof in diiferent positions from those in which they are shown in FIG. 1; and

FIG. 7 is a view similar to FIG. 6, with the parts of the tool in different positions from those in which they are shown in FIGS. 1 and 6.

Referring now in detail to the drawings, there is shown therein a powder actuated tool forming one embodiment of the invention and including a barrel housing 10 of toughplastic -material and a breech housing 12 also of tough plastic material and having a tubular portion 13 and a hollow handle portion 14 integral therewith. The tool includes a simple, very effective recoil absorber 15 adapted to remove about of the force of recoil when a cartridge 17 is tired to drive a fastener 18. The recoil absorber includes a piston-like cup 19 having a flat base 20 and an externally cylindrical, internally tapered `rim 2l, and also includes an elongated, plug-like pad 22 of resilient, compressible material. The cup 19 lits onto a tapered forward end 25 and annular shoulder 26 of the pad 22. The pad and cup are slidable along a liner 23 positioned in counterbore 24 in the breech housing, and the cup normally is urged against the end of the counterbore 24 ,by the pad. The pad is highly compressible and preferably is composed of foam plastic material capable of high energy absorption when compressed and also having a relatively slow recovery characteristic. One very excellent material for the pad 22 is an expanded, foarnlike polyurethane material sold under the mark Profoam 9389 by the Xenon Corporation. The cup 20 preferably is composed of tough, substantially rigid nylon and acts to hold the pad under an initial longitudinal compression along with a cap 29 screwed onto threaded portion 3i) of the breech housing 12. Preferably the pad when in its normal position, as shown in FIG. 1, completely lls the chamber within the breech housing between retaining cup 19 and end cap 29, and is precompressed to a length only about 90% of its normal, unrestrained length. The pad 22 preferably has a smooth, molded cylindrical surface 31 fitting closely and slidably in the liner 23. A lubricant of, for example, silicone is provided between the liner and the cup 19 and the pad 22. Preferably the pad 22 has a slow recovery time of at least a large fraction of a second, so that its rebound force is negligible. The pad has a large number of small air cells therein, preferably being of a density of approximately 15 pounds per cubic foot.

A guard 36 is carried by the barrel housing 10. A barrel sleeve 38 is connected to a headed, barrel or muzzle portion 40 by an internally flanged coupling ring 42, which is threaded internally. The barrel sleeve 38 is adapted to receive reduced, sleeve portion 44 of a piston cage 46 forming a portion of a power plug assembly 49. The piston cage 46 has a head 48. A cartridge-holding power plug 50 having an enlarged head portion 51 and a threaded shank portion 52 is screwed into an internally threaded portion 54 in the piston cage 46. The cartridgeholding power plug 50 is adapted to carry the cartridge 17 The sleeve portion 44 also includes collet-like fingers 56 delined by longitudinal slots 5S positioned therebetween and serving to frictionally engage a captive piston 69. The piston has a ram portion 61, an enlarged piston portion 63 and a frustoconical transition portion 65. A spring 62 is seated between the end of sleeve 64 of the guard 36 and an internal shoulder 66 of the barrel housing 10. A compression spring 63 seats on the internal shoulder 66 of the barrel housing 16 at one end and seats against an annular shoulder 711 of the ring 42 at the other end. The spring 68 is positioned coaxially with and inside of the spring 62 and extends into the sleeve 64 of the guard 36, which is splined to the barrel sleeve 38 by means of a pin 74 ixed in bore 76 in the barrel housing and a slot 78 formed in and extending along the sleeve 64. While the slot 7S is shown 180 from a slot 245 in the sleeve 64, the slot 78 and pin 74 preferably are posi- :tioned about 135 from the slot 245 to insure proper insertion of the guard 36 into the barrel housing.

A breech block 80 having arms 81 and 82 is mounted pivotally on the barrel sleeve 38 by a pin 83 positioned offset from the axis of the sleeve 38 and the longitudinal axis or centerline of the breech block 86. A set screw 85 (FIG. 3) screwed into a tapped bore 79 in the barrel sleeve 38 holds the pin rigidly to the barrel sleeve and the pin has a groove $9 to provide clearance for the sleeve portion 44 of the piston cage 46. This hinging structure permitting opening or breaking of the tool is substantially like that disclosed and claimed in Patent 2,977,598. When the powder actuated tool is in its normal position, as shown in FIG. 1, the barrel khousing 10, being urged by the springs 62 and 68, extends over the breech block 8@ and engages the forward end of the breech lblock housing 12. rl`he powder actuated tool when in its normal or closed condition as shown in FIG. 1 may not be opened to Vremove the piston cage 46 with the captive piston from the tool. Opening or breaking of the tool may be eiected by first sliding the barrel housing 10 to the left against the action of the spring 63 until the righthand end of the barrel housing 11i is to the left of the pin 553, and then the breech :block 81) with the breech housing 12 may be pivoted on the pin 83 away from the plug 5t), and the piston cage 46 with the captive piston 69 lmay be withdrawn from the barrel sleeve 33 to eject the cartridge 17 and also slide the captive piston 6i) back into its normal starting position in the piston cage 46, in which position it is shown in FIG. l, and insert a loaded cartridge. Such sliding of the captive piston 60 serves to eject the cartridge 17 from a chamber 84 in the plug 5t). A reduced end portion of a screw 91 (FIG. l) screwed into tapped bore 93 in the breech housing 12 projects into splining slot 9S in the Ibreech block 80. Shoulder 97 at the end of the slot 95 limits movement of the breech block to the left relative to t-he breech housing.

The captive piston 6G is provided with a combined gauge and ejector S5. After the piston cage 46 is placed, with a fresh cartridge 17 in the plug 50, in the barrel sleeve 3S, lthe breech block 80 and the breech housing 12 are swung back int-oalignment with the barrel sleeve 38. The barrel housing 1@ then is released and is moved back over the breech block 80 by the spring 68 to the normal position thereof shown in FIG. l.

The fastener 18 has a reduced, pointed shank portion 86, a larger shank portion 87 and an enlarged head 88. The fastener is inserted manually into the muzzle portion 49 until the head 8S engages an inner, annular shoulder 91D in the muzzle portion 46, which prevents insertion into the tool of excessive length fasteners which would cause excessive recoil. After such loading, the tool may be placed against a surface into `which the fastener 18 is t0 be driven and then the breech housing 12 and the `barrel housing 1th are pushed forwardly relative to the barrel sleeve 3S, the muzzle portion 40 and the breech block 8l), which is slidable in a lining sleeve 94. The breech housing 12 .moves along the breech block Sti until the cup 19 engages end plate 96 carrie-d by the breech block. The partial precompression of the pad 22 is several times greater than the combined forces of the springs 62 and 68 when the tool is in the cocked or tiring condition thereof show-n in FIG. 6 so that, to the user who has pushed the handle 14 to bring the tool to its cocked condition7 the increase-d resistance of the pad to further forward movement of the handle and breech housing appears to be a positive stop, whereby the user readily senses that the tool is in its cocked condition and is ready to be fired. This partial precompression of the pad prior to any movement of the cup 19 away from the stop shoulder at the end of the counter- -bore .'24 also provides a substantialinitial resistance to recoil movement of the floating firing mechanism, which includes the breech block 30, the barrel sleeve 38, the muzzle portion 4d and the elements carried with these elements. This initial resistance makes optimum the recoil resisting action of the pad 22.

As the breech housing 12 is moved forwardly relative to the breech block S9 to lbring the tool to its cocked condition, a safety hook portion 114B of a trigger 112 mounted pivotally in slot 114 in the handle 14 by a pin 116 moves forwardly beyond pin 11S secured in aligned bores on the opposite sides of a longitudinal slot 120 in the breech block Sti. This permits the trigger 112 to be moved manually from the position thereof shown in FlG. 6 to that shown in FIG. 7. The pin 116 is secured in aligned lbores in the handle 14. A hammer 124 having a rounded end 122 is mounted pivotally on a pin 126 tting into bores in semi-cylindrical projecting portions 12S of the breech block 80 and extending across a slot formed between the members 12S. During s-uch movement, the end 122 engages an L-shaped sear 138 mounted pivotally on a pin 132 seated in aligned bores in the handle 14 and the sear 131i prevents movement of the lower end 122 of the hammer 124. A spring 129 urges the sear toward its latching position. This pivots the hammer 124 clockwise as viewed in FIG. l against the action of a pair of springs 133 positione-d in bores 134- in the members 128 and bearing against the plate 96 and spring seats 136 formed on the ends of pin 138. The plate 96 is secured by screws 139 to the members 128. The pi-n 138 extends through parallel, laterally `aligned slots 141B and is movable along the slots 140. When the plate 96 reaches the cup 19, the hammer 124 is in the cocked position thereof shown in FIG. 6. Then, when the trigger 112 is pivoted counterclockwise as viewed in FIG. 6 to the position thereof shown in FIG. 7, the end of the sear 130 engaging the rounded end 122 of the hammer 124 moves -downwardly out of engagement with the hammer 124 and the springs 133 and pin 138 move the hammer 124 rapidly in a counterclcckwise direction to 4cause hammer portion 146 of the hammer to strike rounded end 148 of firing pin 150. This drives reduced end portion 152 of the firing pin into tiring engagement with the cartridge 17. The ring pin is mounted slidably in a bushing 153 mounted in recess 154, the 'bushing 153 being hollow and containing a compression spring (not shown) engaging a shoulder on the iiring pin and urging the firing pin 150 toward the right as viewed in FIG. 6 to normally keep the firing pin from projecting to the left beyond the end wall of the breech block to prevent damage to the point of the firing pin by the power plug when the tool is being opened and closed. The springs 133, when in the positions thereof shown in FTG. 1, are substantially 'fully extended so that no appreciable force is applied thereby to the hammer 124 and the hammer, lbeing stationary at this time, applies no appreciable force to the firing pin. A port 159 is connected by a passage (not shown) in the bushing 153 and by clearance around the portion 152 of the firing pin to permit gases to escape from the cartridge 17 into the space between the members 128 in the even of puncture of the cartridge 'by the firing pin. This prevents build up 4of excessive pressure in the -recess 154.

Upon triggering, the cartridge 17 is tired and gases are emitted from the lefthand e-nd thereof as viewed in FIG. l to drive the captive piston 60 to the left, at a relatively low velocity with a high momentum, because of the mass thereof, into engagement with fastener 18. This drives the `fastener 18 -fully up to the portion 87 into the surface engaged by the tool. Full force of the explosion is applied to the captive piston 60 during lthe main portion of the travel of the captivev piston. Then, as the righthand end of the piston as viewed in FIG. 1 arrives at the slots 58, the gases are ported through the slots 58 and a port 155 in the barrel sleeve 38 to rapidly relieve the force of the explosion from the captive piston. That is, the pressure of the gases of explosion are vented before the fastener is driven the desired distance, and the energy in the moving captive pisto-n completes the driving of the fastener the distance desired.

The breech block 80, the barrel sleeve 38, lthe muzzle portion 40, the rin-g 42, the piston cage 46, the power plug Si), the firing pin 150, the hammer 124, the springs 133, the pin 138 and plate 96 comprise a floating firing mechanism. The tiring mechanism is freely slidable along the barrel housing 10 and breech housing 12 to the right, as viewed in FIG. 1, except for the restraining actions of the spring 68 and the recoil absorber 15, which absorb the forces of recoil on the iiring mechanism, these forces being absorbed primarily by the recoil absorber.V The ring mechanism also floats freely relative to the guard 36 so that, during recoil, the guard remains in guarding position against the work. Since, forcewise, the recoil absorber is positioned between the handle 14 and the firing rnechanism, all but a negligible portion of the shock or recoil is isolated from the han-die.

The forces of recoil from the explosion of the cartridge 17 applied through the cartridge and the cartridge holding power plug 5l) to the breech block 80 drive the breech block 89 to the right as viewed in FIGS. 6 and 7 from the tiring position thereof shown in FIG. 6 to the fully recoiled position sho-wn approximately in FIG. 7. This compresses the pad 22, to, it is believed, about onehalf of the volume normally occupied thereby in the breech housing 12, and the pad abs-orbs most of the force of recoil, in a tool forming one constructed embodiment of the invention the pad absorbing about 90% of the force of recoil. Then, the spring 68 which has been compressed during the recoil returns the barrel sleeve 38, muzzle portion 411 and breech block 8) to the initial, firing positions thereof. The pad 22 has a slow recovery time so that it does not exert any appreciable rebound force on the breech block S0 during or after the recoil.

While the recovery is slow, it is effected within a few seconds after the return of the barrel sleeve 38, the muzzle portion 40 and breech block 80.

After the breech block returns to its firing position, it, yof course, .carries the hammer 124 back to the left as viewed in FIG. 7. If the trigger 112 is still held by the user in its tiring position, the sear 1319 is held down out of the `path of the hammer 124 and the hammer 124 remains in an uncocked position. This also is true when the trigger 112 has been released because the rounded end 122 of the hammer will depress and pass over the lefthand end of the sear 130. Then the user relaxes the forward lpressure on lthe handle 14 and `the breech housing 12 and the barrel housing 10- are both moved back to the right t-o the lpositions thereof shown in FIG. 1, and the iirin-g mechanism including the breech block 80, the barrel housing 38, the muzzle portion 40 and the power plug carried by the barrel sleeve 38 all .remain stationary while the @breech housing 12, barrel housing 10 and the handle 14 move to the right. During this latter movement the pin 118 moves under the hook 110 lof the trigger 112 if the.trig:ger 112 has been released byv the user. If the trigger 112 has not been released by the used, the pin 113 moves under the hook and returns the trigger to its normal position a-gainst all but a very strong force holding the trigger in its ring position. The hook 110 is suficiently long and pivotal movement of the trigger 112 to effect firing is suiiiciently short, being limited Iby stop portion 141, that the free end of the hook 110 is never out of the slot 120. Hence, the pin 118 can never go on past the hook 110.

The ram portion 61 ofthe captive piston 6u is joined to the enlarged piston portion 63 thereof Iby the transition portion 65 which is frustoconical and which is of reduced hardness so that it is extrudable. The transition portion 65 is complementary in shape to a frustoconical portion 151 leading to a counterbore 149 in the muzzle portion 40 which counterbore 149 is of larger diameter than the ram portion 61 arid -of lesser dia-meter than the piston portion 63, so that, if the tool is accidentally fired with insufficient resistance to movement of the fastener -or with no fastener therein, the frustoconical portion 151 will draw the transition :portion 65 of the captive piston 60 to dissipate the kinetic ener-gy of piston 6() and prevent the danger. However, when this happens, it sometimes damages the muzzle portion 40, as would be expected, and the muzzle portion 40 may be replace-d with an undamaged muzzle portion merely by removing the guard 36 and turning the muzzle portion 48 to turn ring 42 through a keying pin 173 and then sli-ding the muzzle portion 40 out of the ring 42 and placing a new muzzle portion in the 1in-g. The pin 170 fits ove-r a llat 171 at the end of an enlarged head 172 of the muzzle portion 4t) and also ts into a bore 174 in the ring 42 to rigidly key the muzzle portion to the ring 42.

The sleeve 64 of the guard 36 has a reduced muzzle end portion 178 fitting into a fbore 180 positioned eccentrically in a cylindrical disc 182 and fixed thereto against t rotation. The outer periphery of the -disc 182 has a flange 184 on which is rotatably positioned a cup-shaped shield ymember 186 having a bore 188 eccentric to the periphery thereof fitting rotatably on the disc 182 and held between the ilange 184 and a disc 19t) secured to the disc 182 by rivets 192. The vdisc 19d has an eccentric bore 194 therein aligned with the bore 186 in the disc 182. By rotating the shield member 186 relative t=o the discs 182 and 19d, the eccentricity `of the member 186 relative to the muzzle portion 411' may lbe adjusted as desired by the user.

The barrel housing l@ near the forward end thereof has a thickened portion 20@ provided with a slot 202 therein in which is fitted tightly a channel-like insert member 204 mounting a latching dog 206. Whenever the sleeve 64 of the guard 36 is pulled out of the barrel housing 10, the dog 208 enters an annular, undercut groove 210 in the coupling ring 42 to hold the barrel sleeve 318 against movement to the right relative to the barrel housing. Cup-shaped inserts 220 and 222 secured in holes in the barrel housing carry pivot pins 224 and 226,- respect-ively. Latching dogs 22-8 and 230 are mounted pivotally on the pins 224 and 226, respectively. The dog 228 is urged counterclockwise into slot 232 in the guard sleeve 64 to prevent removal of the guard sleeve from the barrel housing unless the dog 228 is pressed manually out of the slot 232. When the muzzle portion 40 is replaced with a longer muzzle portion where desired for certain uses, the shield can still be held in the position shown in FIG. 1 by the dog 223 or the shield can be held in a second position to the left of that shown, in which second position the dog 228 projects into a slot 236 in the shield sleeve to limit movement of the shield to the left relative to the barrel housing 10. The dog 228 is urged by a torsion spring (not shown) in a counterclockwise direction, as viewed in FIG. l, into the slot 232 and is designed to engage web 241 to limit movement of the guard sleeve 64 t-o the left. The dog 230 is urged clockwise by a torsion spring (not shown) into the slot 236', and is designed to be engaged by the web 241 to limit movement of the guard sleeve 64 to the right. The sleeve 64 is shown in a retracted or shortened position in FIG. l, and, when desired, may be adjusted to an extended position in which the dog 228 projects into the slot 236 and engages web 243 and the dog 230 projects int-o slot 245, to limit movement of the sleeve 64 to the right. The dogs 228 and 230 can be pressed manually to retract them from the slots in the sleeve 64 to adjust the sleeve 64 along the barrel housing 10 or to remove or insert the sleeve 64 into or out from the barrel housing.

Since the recoil absorber is positioned between the handle 14 and the free iloating tiring mechanism, the force of recoil is dissipated before reaching the user eX- cept for the negligible, slight residue which is a small fraction of the total force of recoil. Hence, the user has no unpleasant or dangerous kick imparted to him. The trigger mechanism will not fire on accidental dropping of the tool. Also, the power plug 50 being replaceable, the tool can be readily adapted to cartridges of different sizes. Since the cap 29 is removable from the breech housing, the pad 22 and cup 19 can be easily extracted for purposes of maintenance or replacement.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. In a powder actuated tool,

a breech housing,

pad means of resilient, compressible material mounted in the breech housing and maintained normally in a partially precompressed condition, breech means adapted to carry a cartridge and slidable along the Ibreech housing from a forwardly located normal position out of engagement with the pad means into engagement with the pad means at a rearwardly located tiring position and also movable rearwardly trom the tiring position to a recoil position,

and tiring means adapted when the breech means is in the firing position thereof to tire a cartridge carried by the breech means.

2. In a powder actuated tool,

a generally tubular breech housing closed at the rear end thereof,

a pad of resilient foam material mounted in the rear end portion of the breech housing and compressible rearwardly in the breech housing,

a retaining member engaging the forward end of the pad and slidable rearwardly along the breech housing from a forward position,

and breech means slidable rearwardly in the breech housing from a `firing position in engagement with the retaining member.

3. The powder actuated tool of claim 2 wherein the retaining member when in its forward position holds the pad under compression.

4. In a powder actuated tool,

a hollow breech housing,

a cushioning member of resilient compressible foam material positioned in 'the breech housing,

breech means slidable rearwardly along the breech housing fnom a forward position out of engagement with the cushioning member to a tiring position in which the cushioning member -rst resists rearward movement oct said breech means and also being slidable rearwardly along the housing Ifrom the tiring positdon during recoil,

and trigger means coekable by relative movement of the breech means Ifrom its forward position to its tiring position.

5. In a powder actuated tool,

a generally tubular breech housing `closed at the rear end JUhereof,

pad means ott resilient, `foam material mounted in the rear end portion of the breech housing,

breech block means slidable relatively rearwardly in the breech housing from a Iforwardly located normal position out of engagement with the pad means to an intermediate thing posi-tion in which the pad means rst resists rearward movement of said breech block means, and slidable rearwardly in the housing from the ring position thereof during recoil -to further compress the pad means, whereby `the pad means absorbs the energy of recoil,

sear means carried by the breech housing,

hammer means carried 4by the breech block and engaging fthe sear means and being cocked thereby as .fthe breech block means is moved from its normal position relative to the breech 'housing to its tiring position,

and trigger means carried by .the breech housing tor actuating the sear means to release the hammer means.

v6. In a powder actuated tool,

a breech housing having an open front end thereof and a closed rear end,

a breech block slidable in the breech housing toward the rear end thereof during recoil,

and pad means of resilient, compressible, foam material positioned in a chamber within the breech housing between the breech block and the closed rear end of the breech housing, said pad means substantially cornpletely till-ing said chamber `and adapted to be compressed by the breech block during recoil of the breech block.

7. In a powder actuated tool,

a breech housing having an open front end thereof and a closed rear end,

a breech block slidable in the breech housing toward the rear end thereof during recoil,

a pad of resilient, -compressible yfoam material positioned in Ithe breech housing between the breech block and the closed rear end of the breech housing,

and a rigid member slidable in the breech housing, en-

gaging the forward end of the pad and adapted to be engaged and pressed against the pad by the breech block during recoil of the breech block.

8. In a powder actuated tool,

a breech housing having a forwardly positioned cylindrical bore and also having a rearwardly positioned counterbore -aligned with the bore .and having a predetermined diameter and a predetermined length,

an elongated, cylindrical pad of resilient, compressible material having a diameter substantially the same as said predetermined diameter and having a length substantially greater .than said predetermined length,

restraining means positioned lin :the oounterbore and enga-ging the front end of the pad,

la cap secured to the rear end of the breech housing and holding the pad under longitudinal compression in the connterbore,

anda breech block slidable in the bore and cohn-terbore and adapted to engage the cup and compress the pad during recoil.

9. In a powder actuated tool,

a breech housing having a forwardly positioned cylindrical bore and also having a rearwardly positioned counterbore aligned with the bore and having a predetermined diameter and a predetermined length,

an elongated, cylindrical pad of resilient, compressi'ble material having a diameter substantially the same as said predetermined diameter and having la length substantially greater than said predetermined length,

a piston-like cup of tough plastic material fitting slidably in the counterbore and on the lforward end of -the paid,

a cap secured to the rear end of the breech housing and holding the pad under longitudinal compression in the counterbore,

and a breech block -sl-idable in the bore and counterbore and adapted to engage the cup and compress the .pad during recoil.

10. In a powder actuated tool,

a firing pin,

a breech block having a .centrally positioned slot in the rear end thereof extending transverse to the longitudinal axis of the breech block and also having a ring pin bore extending forwardly from the slot and in which the ring pin is slidably mounted,

a hammer lever 'having a hammer end and la second end,

a pivot pin mounting the hammer lever pivotally in the slot in a position in which the hammer end is adapted to engage the ring pin,

the breech .block being provided with a pair of longitudinal bores positioned at opposite sides Iof the slot and also having a pair of gnideways extending along the bores and opening into the bores and the slots,

a pin extending across the slot and through the guideways and having a pair of clipped spring seats posiltioned in the bores,

a pair of compression springs mounted in the bores and .pressing the pin forwardly against the hammer to urge the hammer forwardly relative to the breech block,

a breech housing mounting the breech block slidably.

the-rein,

a sear carried by the breech :block housing and movable between a cooking position in the path of the second end of the hammer when the breech block housing is moved forwardly relative to the breech block and a firing position releasing the hammer,

and trigger means for moving the sear between the cooking and firing positions thereof.

11. In a powder actuated tool,

a breech housing,

a Vbreach block slidable in the breech 'housing between a forwardly located position and a rearwardly located position,

hammer means movable to a cocked position during relative rmovement of the 'housing and the block in which the block moves relatively to its rearwardly located position,

sear means for releasing the hammer means from its cocked position,

trigger means having a hook thereon and mounted movably on the housing and adapted to actuate the scar means, v

and pin means carried by the block and positioned in the hook when the block is no-t in its rearwardly located position to prevent movement of the trigger means and positioned out of the hook when the block is in its rearwardly located position to permit movemen-t of the trigger means,

12. In a powder actuated tool,

a .breech block having a transverse slot in a predetermined plane at the .rear portion thereof and also having a centrally located firing pin bore extending forwardly from the transverse lslot,

ythe breech block also having a longitudinal slot in the peripheral portion thereof and in said plane,

a firing pin mounted in the bore and normally projecting into the transverse s-lot,

a hammer mounted in the transverse slot `for pivotal move-ment therein and having a hammer portion at one end for engaging the iring pin and also having a cooking portion at the other end thereof,

a transverse pin carried :by the breech block in a position extending across the rear end portion of the longitudinal slot,

spring means urging the pin against the hammer to funge the hammer toward the firing pin,

a breech housing ,mounting the breech block therein for relative movement between a normal position in which the breech block is forward ofthe housing and a firing position in which the breech block is positioned rearwardly in the breech housing,

an L-shaped sear lever carried pivotally in the breech housing and movable between a cocking position in which one end thereof projects into the path of and behind the cooking portion of the hammer and' a releasing position out of engagement with the. hammer,

spring means 'urging the sear toward its cooking position,

and a trigger carried by the breech housing and engaging sear,

the trigger `being urged by the sear toward a normal position and movable manually to movethe sear from the cooking position thereof to the releasing position thereof,

the trigger having a .hook extending along the longitudinal slot and over the transverse pin when the 4block is in its normal position and being free of the pin when the breech block is in its firing position.

13. In a powder actuated tool,

barrel means having a muzzle portion provided with .a bore and a. stop portion projecting into the bore thereof to limit insertion o'f a fastener -into the muzzle por-tion, and a captive piston of la diameter suiliciently small to move freely past the stop portion.

14. In a powder actuated tool,

a generally tubular breech housing closed at the rear end thereof,

breech means including a piston-like retaining member at the rear end thereof and slidable along the forward portion of the breech housing,

and a mass of resilient foam material positioned in the breech housing behind said retaining member and substantially completely lling the space between the rear end of the housing and the retaining member.

15. In a powder actuated tool,

a breech housing having a longitudinal bore closed at the rear end thereof and open at the front end thereof,

breech means slidable rearwardly in the housing from a forward position to a firing position and also slid-A lable rearwardly in the housing Ifrom the firing positi-on to a recoil position,

a cartridge ring mechanism within said housing which is prevented from ring a cartridge when the breech means is in the forward position thereof Vand pe-rmitted to re when the breech means is in the ring posi-tion thereof,

resilient means in the bore in the housing in the path of rearward movement of the breech means,

and Ameans holding the resilient means in a pnecompressed position in which the resilient means rst resists rearward` movement of the breech means when the breech means arrives at the rinlg position thereof.

References Cited by the Examiner UNITED STATES PATENTS Sopris 227--9 Sohulz 227-8 De Caro 227-10 Catlin et al 227-10 X Catlin et al 227-10 Kopf et al 227-10 l0 GRANVILLE Y. CUSTER; JR., Primary Examiner. 

1. IN A POWDER ACTUATED TOOL, A BREECH HOUSING, PAD MEANS OF RESILIENT, COMPRESSIBLE MATERIAL MOUNTED IN THE BREECH HOUSING AND MAINTAINED NORMALLY IN A PARTIALLY PRECOMPRESSED CONDITION, BREECH MEANS ADAPTED TO CARRY A CARTRIDGE AND SLIDABLE ALONG THE BREECH HOUSING FROM A FORWARDLY LOCATED NORMAL POSITION OUT OF ENGAGEMENT WITH THE PAD MEANS INTO ENGAGEMENT WITH THE PAD MEANS AT A REARWARDLY LOCATED FIRING POSITION AND ALSO MOVABLE REARWARDLY FROM THE FIRING POSITION TO A RECOIL POSITION, AND FIRING MEANS ADAPTED WHEN THE BREECH MEANS IS IN THE FIRING POSITION THEREOF TO FIRE A CARTRIDGE CARRIED BY THE BREECH MEANS. 